Blisters sometimes occur during the production of automobile Class "A" molded fiberglass reinforced plastic, e.g., polyester, FRP, parts requiring removal of the blister, filling the hole or void left by the blister with automobile putty, sanding and other refinishing operations which are expensive in time, materials and labor. These blisters may be due to improper mixing or curing of the components, layering of the glass and/or pockets of unpolymerized gaseous or liquid monomer such as styrene which causes expansion or rising of the skin of the molding due to gas expansion and so forth. Blisters may range in size from about 1/4 to 4 to 5 inches in diameter, and the subsequent venting associated with blisters may cause skin rupture. This problem becomes even more severe if the FRP part is mounted on the automobile chassis and passes through the paint tunnels and drying ovens. Here, the solvent has penetrated into a crack or been absorbed into the outer layers possibly due to porosity of the FRP part and on heating causes expansion and formation of a blister requiring the automobile to be removed from the assembly line, the parts removed, reworked as above, repainted and remounted on the chassis, sometimes taking up to four hours. In some cases the entire automobile must be recycled through the painting tunnels and ovens. Moreover, many of the available repair methods do not hold in subsequent operations and may cause severe surface damage or textural change which is evident after painting.
Accordingly, it is an object of the invention to avoid the difficulties alluded to above and to provide an improved method for repairing blisters on FRP parts. Another object is to provide an improved repaired fiberglass reinforced plastic part. These and other objects and advantages of the present invention will become more apparent to those skilled in the art from the following detailed description.